1. Field of the Invention
This invention relates to filters for processing fecal samples to separate parasite eggs and larvae. More specifically, the invention pertains to a filter having connections for a sample vial and a centrifuge tube including a hollow stem for equalizing pressure therebetween, wherein there is an upstanding skirt portion to act as a protector for the one end of the filter when associated with the sample vial. This invention is an improvement to the concentrator and filter described and claimed in issued U.S. Patent No. 5,556,544.
2. Background Art
Previously, many types of filters have been used in endeavoring to provide an effective means for the separation of parasite eggs and larvae from feces samples. Over the years, many types of devices have been developed to concentrate parasitic eggs and larvae also protozoan cysts and to recover coccidian occysts such as isopora belli and crytosporidium parvium.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however, the following U.S. patents are considered related:
______________________________________ U.S. Patent No. Inventor Issued ______________________________________ 5,556,544 Didier September 17, 1996 4,081,356 Zierdt March 23, 1978 4,675,110 Fay June 23, 1987 ______________________________________
As indicated, the invention herein is an improvement over the concentrator and filter of U.S. Pat. No. 5,556,544 in that an upstanding skirt portion extends upwardly to over an end portion of the sample unit so as to prevent contamination, as with fecal matter.
U.S. Pat. No. 4,081,356 to Zierdt discloses a current device and method for recovering parasitic eggs and larvae from feces samples. In this device, a cup is attached to an open ended tube forming an emulsification chamber. A filter is attached to the chamber which includes a coaxial tube for the passage of air and a centrifuge tube is attached by an annular collar to form a separating chamber.
U.S. Pat. No. 4,675,110 to Fay discloses a device and method for the concentration of parasite eggs and larvae. The device consists of separable upper and lower chambers connected by a mid-piece which incorporates a filter of stainless steel gauze.
Other systems and methods have been utilized for the same purposes such as the fecal parasite, concentrator known by its registered trademark FPC and JUMBO and manufactured by Evergreen Scientific of Los Angeles, Calif. The JUMBO concentrator functions in the same manner as described above and connects a vial and tube together as with Fay's teachings. A movable vent-straw is located in the center of the strainer unit and requires manually pulling the straw out approximately 1.0 inch (2.54 cm) prior to attachment of the specimen vial. The problems of clogging and blocking the pressure equalizing element still exist and multiple components are employed.
For background purposes and as indicative of the art to which the invention relates reference may be made to the remaining cited patents.
______________________________________ U.S. Patent No. Inventor Issued ______________________________________ 4,783,318 Lapakko November 8, 1988 5,104,533 Szabados April 14, 1992 5,489,385 Raabe, et al. February 6, 1996 5,482,618 Hall January 9, 1996 5,501,841 Lee, et al. March 26, 1996 5,518,612 Kayal, et al. May 21, 1996 5,534,228 Wesseler July 9, 1996 5,624,554 Faulkner, et al. April 29, 1997 5,601,711 Sklar, et al. February 11, 1997 5,603,900 Clark et al. February 18, 1997 ______________________________________